Question

why does the addition of a salt (like sodium chloride) to the aqueous layer sometimes help break up an emulsion that forms in an extraction?

- sorry about that last post

Answer 1

I think th primary reason is that NaCl is so much more soluble in water. Emulsions, particularly those between water and oil, form with oil droplets being surrounded by water or water droplets being surrounded by oil (depending upon which is in excess). The ions of NaCl have such an attraction for water molecules (in effect we are dealing with highly hydrated sodium ions and hydrated chloride ions) that it isn't hard to break any small attraction between oil and water.

Answer 2

no home work for the year